Survival of HIV-Infected Injection Drug Users (IDUs) in the Highly Active Antiretroviral Therapy Era, Relative to Sex- and Age-Specific Survival of HIV-Uninfected IDUs

In the era of highly active antiretroviral therapy (HAART), it remains unclear whether human immunodeficiency virus (HIV)-infected injection drug users (IDUs) have durations of survival similar to those for comparable HIV-uninfected IDUs. The goal of this study was to compare survival durations of HIV-infected and HIV-uninfected IDUs for the period 1987-2004.Methods. Demographic data, drug use characteristics, and biological markers were obtained at the time of admission to a substance abuse treatment program. The outcome of interest was the duration of survival after admission, and the primary exposure was HIV infection. Vital status was ascertained by means of the mortality register by the end of 2004. Three calendar periods, which were defined on the basis of use of specific therapies, were considered: 1987-1991 (the antiretroviral monotherapy era), 1992-1996 (the dual combination therapy era and the era when methadone was introduced in Spain), and 1997-2004 (the era of HAART and of established methadone programs). We used Cox regression methods allowing for late entries to handle the contribution of persons who survived a given period and entered the following period with nonzero time. We compared HIV-uninfected and HIV-infected IDUs with adjustments for age, sex, and duration of follow-up after admission.